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Flooring and Carpeting/Use of 1" thick granite


Sample Surround
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2nd Sample
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I am tearing out the current brick front fireplace and want to reinstall with 1" thick Cosmos granite. I have concrete floors and the "tile guy" will be building a new surround for the fireplace. I am going to use an electric insert in the fireplace.

The granite company will fabricate the pieces but will not install them. They apparently have had some quality issues and so will no longer install the pieces.I am not planning anything "fancy", I will let the granite be the focal point.The surround will be about 10" deep, 54" high, and 60" long.

My questions are:

1. What type of backer board do we need?
2. If we use 2x4's for the frame will that be sturdy enough?
3. How do we support the granite slabs while they dry?
4. Why type of mortar should we use?
5. Do the slabs need to be braced until the mortar dries? If so, with what and for how long? If not, how do you keep them in place until they dry.
6. Do they need to be bolted to the backer board or is thinset sufficient?
7. If I want to use the granite for the mantel, what special steps do I need to take?

That is about everything I can think of. I've attached a couple of pictures I found that are similar to what I'm looking for. The images are not intended for use, just for an idea of what I'm looking for. If you need further information, please let me know.

Thank you,


Thank you for your question Resa,

     For the sake of brevity I will answer one by one...

1)For this application I would use a cement board only glued and screwed to the framing studs. My personal choice has long been Wonderboard.

2)The 2x4 standard studs will be fine the only thing I would add would be to screw in cross framing between the studs to give some additional rigidity to the assembly.

3)The Granite slabs should require minimal support as the weight of the stone is not born by the vertical wall only the base upon which you have placed the stone. I would purchase some small brass rods (typically 1/16th) and use this material to gage/space the slabs apart if you are interested in having a small grout joint between the material layers. If not then you can apply a small line of Silicone to the backside of the slab to help secure the pieces together once in place, and start with a Construction adhesive like PL-400 to set the base pieces.

4)Depending upon the manufacturer standard for assembly they may not require a mortar between pieces and a simple adhesive may be all that is required.

5)As your pieces are installed you can apply the Construction adhesive to the point of contact between the stone pieces and the cement board that it presses up against. Bracing will only be needed if contact with the vertical wall cannot be maintained...bear in mind that the goal is the entirety of the weight is to be born by the sub-strate that it is sitting upon...follow me?

6)If there is attached blocking to the fabricated pieces that brings the cement board and the stone pieces close together then all that is needed is the thinset liberally placed between them. If there are "thru-bolts" then that will require a much larger access to get behind the vertical wall to put on the washer/nut system if that is what you have. Otherwise apply the adhesive wherever the stone makes contact with the wall and floor.

7)If you want to add a Granite mantle then be sure that the support assembly is both level and plumb. Then you can "cut" into the wall board and create a recess into which the Granite can slide up to the stud and then glued into place. That should be all you need.

Ok Resa I hope this helps you with your project, feel free to return anytime.

Perry V.  

Flooring and Carpeting

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Perry Vellenga


Ceramic Tile/Marble. I can answer questions about floor preparation, tile selection, layout questions, performance of products, expectations of finish, compatabilities, questions about grout and epoxies, evaluating an installer, asking the right questions to check competence...more? 33 years this August 2012/ many years in commercial application from exterior finishes to Mall store fronts/ interior finishes like floor packages in stores inside Malls examples: The Limited, Lerner/NY, Lane Bryants, Bombay Co., Now involved in Residential new construction covering all types of interior finishes and designs.


I worked in an exclusive field of floorcovering called "Tenant Development" which is by invitational bid only, by way of a National bid list. These are large floor packages usually over 3500 sq. ft. of 18" x 18" Marble and Granite and many other types of Marble and sizes. They are specialty stores where the floor package can cost upwards of $50,000 for one store. I have also done "Structure" stores and J. Riggins stores, Lane Bryant,Express and Body Shop stores where wood flooring is used. Presently work for a National Flooring Company in the Residential new construction arena that covers most interior design elements..Granite Slab tops/wood flooring both job finished and prefinished ect..

My response's are published all across the Internet and picked up by multiple Interior Design sites and Industry related web sites where people have questions...

too many most of which don't count...

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